Porsche has been associated with racing from its earliest beginnings, as even before World War II its founder, Ferdinand Porsche, was involved in the Grand Prix scene. And while Porsche has produced many great race cars, the 917 remains a watershed product for the company.

The 917 debuted in early 1969 to win and dominate the Group 4 sports cars and then became legend after winning the Le Mans 24-hour race back-to-back in 1970-71. Being prominently featured in the Steve McQueen film about the famous 'round-the-clock race further immortalized the car.

Porsche also turned its eye to the American market for racing where, at the time, there was only one logical place to put the car to the test: the Can-Am series.

Our featured car is a 917-10 (chassis No. 002), fitted with a 5.0-liter, naturally aspirated 12-cylinder engine making 500 hp, and it was specifically built for Jo Siffert and the 1971 Can-Am season. Siffert started six of the 10 races that year, making the podium three times. In each race, his car was running when the checkered flag flew.

Siffert died in October of that year while in an F1 race at Brands Hatch. With the points accumulated he was classified fourth in the 1971 Can-Am Championship.

Following the conclusion of the season, 917 chassis No. 002 was brought by Porsche back to Germany, where it received updates and preparation for the 1972 Interseries (Europe's version of the Can-Am). The car was purchased by Willy Khausen, a longtime Porsche factory driver.

In the first seven races of the nine-race season, Khausen recorded one victory, five second-place finishes and one retirement because of a flat tire. Midseason, he had the engine upgraded with turbos to stay in the running for the championship.

In the second to last race at the Nürburgring his luck changed, and he had a bad crash, suffering several burns and heavily damaging the car. Khausen borrowed another chassis for the season finale and managed to score a second-place finish that placed him second overall for the season.

Following the crash at the 'Ring, the remains of No. 002 were shipped to Khausen's race shop, where it was stored and nearly forgotten about for the next 25 years.

Fast-forward to 1998, and Khausen decided it was time to resurrect his 917-10. He sent the car back to the factory so that some of the same men who built the car could bring it back to its original glory. He even decided to have it restored to its 1971 livery in honor of Siffert.

After its completion Khausen drove the car several times in demonstration runs, but never again in anger. The car has since changed hands two more times before now being offered at auction at RM's sale in Monterey on Aug 18.

The car is fully operational and vintage race-ready. If interested, bring your checkbook—a piece with this much history surely won't come cheap.